1. Field of the Invention
The present invention generally relates to computer facilitated Web service QoS (Quality of Service) observation, evaluation and selection. Using the invention, a human user is able to observe the QoS of Web services, ranking Web services, and even allows the system to select Web services based on his/her preference.
2. Background Description
Web services are autonomous software systems identified by URLs (Universal Resource Locators) which can be advertised, located, and accessed through messages encoded according to XML-based (extensible Markup Language) standards (e.g., SOAP (Simple Object Access Protocol), WSDL (Web Services Description Language), and UDDI (Universal Description, Discovery and Integration)) and transmitted using Internet protocols (EPs). Web services encapsulate application functionality and information resources, and make them available through programmatic interfaces, as opposed to the interfaces provided by traditional Web applications which are intended for manual interactions. In addition, since they are intended to be discovered and used by other applications across the Web, Web services need to be described and understood both in terms of functional capabilities and QoS properties.
The ever increasing number of functional similar Web services being made available on the Internet, there is a need to be able to distinguish them using a set of well-defined Quality of Service (QoS) criteria. Currently, most approaches that deal with QoS of Web services only address some generic dimensions such as price, execution duration, availability and reliability (see Daniel A. Menasce, “QoS Issues in Web Services”, IEEE Internet Computing, 6(6), 2002; Liangzhao Zeng, Boualem Benatallah. MarIon Dumas, Jayant Kalagnanam, and Quan Z. Sheng, “Quality Driven Web Services Composition”, Proceedings of the 12the international conference on World Wide Web (WWW), Budapest, Hungary. ACM Press, May 2003). However, these generic criteria might not be sufficient for observing QoS of Web service, evaluation and selection.
Moreover, most of the current approaches rely on service providers to advertise their QoS information or provide an interface to query the QoS values, which is subject to manipulation by the providers. Obviously, service providers may not advertise their QoS information in a “neutral” manner, for example, execution duration, reliability, etc.